This is an open label, non-randomized, Phase I dose escalating study of rhIL-12 administered by intraperitoneal (IP) infusion in adult male or female patients with measurable disseminated intraperitoneal cancer that is residual, recurrent or metastatic. Neither a control or placebo group will be utilized. Up to 30 patients will be treated weekly on an outpatient basis with the study drug. Patients will be entered in cohorts of 3/dose tier of recombinant human IL-12 (rhIL-12) at doses ranging from 3-500 ng/kg administered over the first two weeks of each three week cycle for three cycles. The primary objective is to assess the safety and MTD of rhIL-12 when administered by IP infusion in this patient population.